You can combine weak hives if the bees are still alive, yes. If your hive is weak you can also requeen.
All my bees died so I had to start fresh with a couple thousand bees and a queen. As long as they don't die of an awful disease you can reuse the hive. The new bees will clean out the dead bodies, but there was probably 60,000 dead bees in each of my hives. I got most of them out because I couldn't stand the thought of "here's your new home, sorry about the dead bodies" and I also want them to start building comb and bringing in pollen and not spend days as undertakers. Our season is too short for that. I don't even have a garden in (just some garlic from fall that's looking really good).
All my bees died so I had to start fresh with a couple thousand bees and a queen. As long as they don't die of an awful disease you can reuse the hive. The new bees will clean out the dead bodies, but there was probably 60,000 dead bees in each of my hives. I got most of them out because I couldn't stand the thought of "here's your new home, sorry about the dead bodies" and I also want them to start building comb and bringing in pollen and not spend days as undertakers. Our season is too short for that. I don't even have a garden in (just some garlic from fall that's looking really good).